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Advanced Authoring - LabTALK - Details of Core language This page describes in greater detail the core of the BASIC language used in LabTALK. Again it is not a tutorial about programming and it assumes users have some knowledge about programming. It is here more for reference and in form of examples. If you don't know what a for-next loop does then it won't help you to know its syntax. Loop: for - next The loop expects to be counting only upwards and its syntax is as in the example below for i = 1 to 10 print i next i You can exit from loop anytime by simply overwriting the loop variable value for i = 1 to 10 print i if (i > 4) then i = 10 endif next i loops can be also nested for x = 1 to 10 for y = 1 to 10 print x,",",y next y next x Condition: if -then- else -endif A typical basic condition using if - then a = 10 b = 20 if (a+b 30) then print"true!" endif You have to always close if with endif! a = 40 b = 20 if (a+b 30) then print"true!" else print"false!" endif Inside the condition you can use these boolean operators and these operands: Printing to screen: print, trace, print msg Printing values of variables is done with print command. There are few flavors of it, each has the same syntax: The syntax of all print commands is simple. Consider the sample below: a = 10 b = " Hello" print"just text" print a print a+10 print"Variable:", a print"Variable:", a ," String", b Input command This command is used to popout an input dialog where user can change one or more variables. A simple usage is this: a = 10 input"Set variable a", a When you run the script a labTALK input dialog will be shown: Obviously there places for more variables on the input dialog and indeed, you can use: a = 10 b = "string" input"Set variable a", a, "Set String", b Running this will show: Special input commands. The input dialog can also modify the way how you enter the data. Checkbox This is done by setting CHECK: inside the string a = TRUE input"CHECK:Set checkbox", a File box with browse button This is done by setting FILE: inside the string a = "C:\\myfile.txt" input"FILE:Set file", a Color box with color selection button This is done by setting COLOR: inside the string a = RGB(255,0,0) input"COLOR:Set color", a Option box (combo box) The options follow after ':' and are divided by '|'. The variable is from 0 ...number of options -1 a = 1 input"Select Option:Option 1|Option 2|Option 3", a In the above example, the return value (in "a") will be 0, 1 or 2. A variable bCancelInput will become TRUE if user press Cancel on the input dialog. A code below will exit the script if user press Cancel: input "COLOR:Select Color ", color1 //allow cancel ifbCancelInputthen trace"Cancelled" end endif end - finish script The command end will simply finish the script ifbCancelInputthen end endif It is not necessary to put "end" at the end of script, but if you have subroutines, you have to put end before them, see gosub below. goto - go to a label The label is a number. Any number will do. Please do not confuse the labels with line numbers. It has nothing to do with them. 10 input"Value 1 or 2", a if (a 1) then goto 100 endif if (a 2) then goto 200 endif print"I can understand 1 or 2" goto 10 100 print msg"You entered One" end 200 print msg"You entered Two" end The program will loop untill you enter 1 or 2 then it will display the message. The labels don't have to be in sequential order, but it makes the program look more logical. (The numerical labels come from the time of first computers when every line written in BASIC had its own number, but we no longer use that so only the labels remained) Gosub - go to subroutine Subroutines in BASIC have to be at the very end of the script and must be labeled by label number (this has nothing to do with line numbers). Returning from a subroutine is done with the return command.print"1" gosub 100 print"2" end 100 print"subroutine" return The printed result will be: 1 subroutine 2 Note the end command before the subroutine will finish the script. It is required to have an "end" statement before you write any subroutines.